WASHINGTON – Europe’s economic crisis could send shock waves roaring across the Atlantic that would drag down the fragile U.S. economy and threaten President Obama’s hopes for a second term. The president demonstrated Friday just how deeply he’s worried about that — and how little he can do to prevent it.

Obama used an impromptu news conference to prod European leaders to quickly and vigorously deal with their crisis. Along with that rare cross-Atlantic jawboning, he accused congressional Republicans at home of holding back a U.S. rebound.

The president held forth, unprompted, on what European leaders could and should do to fix their economic woes, although he insisted he was not “scolding them or telling them what to do.”

He never mentioned his election opponent, Republican Mitt Romney. But the campaign seemed to be an important factor in the day’s events.

Powerless to take on the economic mess overseas by himself, Obama tried to show Americans he was nonetheless engaged in trying to help by offering ideas and advice. At the same time, he was sending a message to his European peers to be resolute and move firmly.

“Now, the good news is there is a path out of this challenge,” Obama said. “These decisions are fundamentally in the hands of Europe’s leaders, and, fortunately, they understand the seriousness of the situation and the urgent need to act.”

Demonstrating his limited direct influence in Europe at the same time he’s being thwarted at home by Republicans on his domestic agenda could reinforce a sense of presidential powerlessness — not an image an incumbent seeking re-election wants to project.

But Obama tried to tie the two issues together to his advantage.

Along with a specific recommendation that Europe inject much-needed money into its banking system, he said European leaders must focus on economic growth and job creation, not just “cutting and cutting and cutting” spending to deal with debt problems. That’s the same point he’s trying to make to Congress — and to voters — back home.

Obama did not go as far as to say Republican lawmakers were rooting for economic failure to undermine him, as his aides have suggested. But he did suggest they may be stalling on his jobs proposals simply because it’s an election year.